My head hasn't been in the drug game lately, so I missed this story at Narco News from a few days ago:

Another series of leaked State Department cables made public this week by WikiLeaks lend credence to investigative reports on gun trafficking and the drug war published by Narco News as far back as 2009.

The big battles in the drug war in Mexico are “not being fought with Saturday night specials, hobby rifles and hunting shotguns,” Narco News reported in March 2009, against the grain, at a time when the mainstream media was pushing a narrative that assigned the blame for the rising tide of weapons flowing into Mexico to U.S. gun stores and gun shows.

Rather, we reported at the time, “the drug trafficking organizations are now in possession of high-powered munitions in vast quantities that can’t be explained by the gun-show loophole.”

Those weapons, found in stashes seized by Mexican law enforcers and military over the past several years, include U.S.-military issued rifles, machine guns, grenade launchers and explosives.

The State Department cables released recently by WikiLeaks support Narco News’ reporting and also confirm that our government is very aware of the fact that U.S military munitions are finding their way into Mexico, and into the hands of narco-trafficking organizations, via a multi-billion dollar stream of private-sector and Pentagon arms exports.

The Zetas, the baddest narco-motherfuckers on the block these days, were trained by the U.S. School of the Americas. (More on that story here.) Apparently, they're still getting their guns from the top of the arms-distribution chain.

“It’s unclear how cartels are getting military grade weapons,” the AP report states.

Well, that's the infernal elegance of our prohibitionist drug policy—because 100% of the industry lives underground, pretty much everything is unclear.